According to several studies, nursing, especially in hospital settings, is one of the most stressful professions. The objective of this study was to identify the sources of stress related to the administrative tasks of nurses working in a hospital, as well as the main health changes that stress caused these professionals. The quantitative survey was carried out in 1996 with a sample of 207 nurses at a university hospital in the city of Porto Alegre, in the state of Rio Grande do Sul, Brazil. A questionnaire was used to collect data on stress sources and symptoms. The questionnaire also gathered demographic data, as well as information on the nurses' feelings about their working conditions. The average age of the study participants was 35.8 years, and the average time working at the hospital was 8.5 years. Among participants, 48% were considered to be stressed. Work overload was the stress source that best predicted relative risk of stress (6.1). In terms of stress symptoms, the most commonly reported ones were cardiovascular changes. However, gastrointestinal changes were related to a higher risk of stress (5.3). Managing other staff was the stress source that had the greatest number of significant correlations with stress symptoms. On the other hand, immunologic changes were the symptoms that had the highest correlation with stress sources. Our results suggest that stress related to administrative tasks in nursing may trigger changes in nurses' health.